External thread gauge



Aprii 6, 1954 H. H. GATES EXTERNAL THREAD GAUGE 2 Sheets-$he6t 1 Filed April 22, 1952 H. H. GATES EXTERNAL THREAD GAUGE I April 6, 1954 Filed April 22, 1952 2 Sheets-Sheet 2 J 4% war/ fizz Patented Apr. 6, 1954 NIT-E PAT O F F EXTERNAL THREAD GAUGE HesslanH; ,Gates, Charlestowm-N. H., assignor. to v Bryant Chucking Grinder Company, I Springfield; Vt.-', a--corporation of Vermont Application April 22, 1952; SerialNo,283,685

" 3 Claims. (ClI33 -199) This invention relates to means for,gaging external threads and is particularly concerned with the construction of .the gaging anvils.

' It has for one object to soiform a cooperating pair of anvils that when they are open, the work may be inserted without requiring it to be rotated and with merely an axial motion. thereof.

A further object'is to provide unthreaded portionsfor the anvils which act to guide-thework piece into and Y out of gaging relation without contact with threaded portions of theanvils, thus to facilitate rapidloading and unloading of the work without wear on or possibility of damage to the threaded gaging portions of the anvils, and to facilitate rapidthrea'd inspection.

' Stillanother object is to provide anvils which can be manufactured accuratelyand at low cost.

"For acompleteunderstanding of this invention, reference. may be had to the accompanying drawings'in which Figure 1 isa top plan view'of a thread gage employing anvils 'embodying'the invention.

Figure 2 is a fragmentary view partly 'in front elevation andpartly broken away and'in section on line 2-2 of Figure 1.

Figure 3 ;is an ziSOIIlGtIiO view of one. I of f the anvils.

Figures i and 5 are fragmentary plan views to a larger scale showing the'anvils in open and closed positions;respectively;

Figure-G is adetailsectional view onf'line 6"6 of 'l5igu-1'e 4.

Figure 7 is a detail sectional view on line l-'I of Figure 5.

Figures 1 and 2 show the gaging elements of this invention applied to an external thread gage of the type shown in the patent to Elton S. Cornell No. 2,581,001 granted January 1, 1952, though it should be understood that the gaging anvils of this invention may be applied to any thread gage wherein the anvils are given a relative motion from and toward each other transverse to the work axis to open or close the anvils with relation to the work to be gaged.

As shown herein one anvil element I is secured to a fixed support 2, the cooperating anvil 3 being fixed to an arm 4 which is pivoted as on the reeds 5 and 6 which pivotally support the arm 4. The lateral extension I of this arm engages the shank of a dial indicator 8. The gage may be opened by pressing together the finger elements 9 and 9a against the action of a spring 4a, the element So being connected to the arm 4.

The anvils are shown more in detail in Figures 1, 2 and 6. The anvil I has a base I which is .secured'to the upperface offlthe support r2 as by the screws I I. f' Spacedabove the portion Illit has a laterally projecting portion I2 which vfaces the anvil.3.r This portion I2 is provided with an extensive as is consistent with other requirements as will later appear.

The gage anvil3, secured to the arm], is provided with a recess 14 opposedto thej recesslIS "of the anvil I but of a greaterwidth. 'I'hisrecess "14 is formed by three arcuate portionsfIl,;I8 and I0.

Theportionsill and I0 are arcs of cyl-,- inders of a diameter. slightly greaterjthan the major diameter of thejwork piece intended, to be gaged and the two arcs are struck about a center 22 (Figuresxl' and lying in the'central line of motion'ofvftheanvil 3' whenvmovingvbetween open and closedposition, and so arranged that the distance between'the edges '20 and"'2I at the edge of the recess I4 is lessithan the major diameter of the work piece to be gaged, so that when a work" piece W "is positioned within I the recess I4, as shown in Figurefii itbannotlbe moved laterally out of i the recess betweenlthese edges and 2I. The 'arcuate'portionI8'inthe recess I4 is formed with internal threadridges 2'5 struck about a center 26' also in the same line of motion as the center 22; but further from the outer face of the anvil 3 which is adjacent to the anvil I. This center 26 is also the center oi the arcuate threads I5 of the anvil I when the anvil 3 is in closed position corresponding to anvil spacing for and with the same radius as that of a standard threaded piece of the size for which the gage is intended. The confronting faces 30 and 3I of the anvils are arranged perpendicular to the line of motion of the movable anvil between closed and open position and are arranged so that there is a slight clearance therebetween when the anvils are closed against a work piece just under tolerance size so that they are capable of gaging such a work piece. As shown also, each of the threaded portions of the anvils is provided with a dirt-receiving recess having sharp dirt cutting edges 36.

When the anvils I and 3 as in Figure 4 are separated the gage is in open position conditioned for inserting or withdrawing the threaded work piece to be measured. This inserting and withdrawing is done by guiding the work piece along the edges 20 and 2I of the arcuate portions l1 and I9 whereby the work piece will be entirely out of contact with the threaded portions at l5 and I8 of both anvils. The inserting is further facilitated by the chamfer 3? at the top of the arcuate portions l1 and IQ of anvil 3. With the work piece now placed in desired axial position the gage mechanism is actuated towards the closed position as in Figures 1 and 5, or as illustrated the anvil 3 is moved towards anvil I. The threaded portion 18 of anvil 3 thereby engages the work piece carrying the work piece into engagement with the threaded portion of anvil I. The gage is now .conditioned for measurement reading and dial 8 will show whether or not the work piece is of stand-' ard diameter on its threaded portion. In again opening the gage the anvil 3 disengages the work piece. This means that the operator of the gage is only required to place the work piece in the axially correct position and read the indicator without having to pay attention to engaging or disengaging the work piece relative to the gage, a feature of importance as it makes it possible to gage thousands of work pieces per hour with the least fatigue.

I claim:

1. A pair Of cooperating external thread gaging anvils adapted for relative motion in one direction toward each other to gage threads and away from each other to open to receive or release a threaded work piece, one of said anvils having a recessed side face having thread gaging ridges in an arc of less than a semicircumference, the other of said anvils having a recessed face opposed to the recessed face of said one anvil, the outer portion of said other anvil recessed face comprising cylindrical arcs each of a diameter slightly larger than the major diameter of the largest work piece to be tested by said gage and having a common center, the remainder of said recessed face of said other anvil having thread gaging ridges described about a center common to the thread gaging ridges of said one anvil when said anvils are in normal closed thread gaging relation and of a radius equal to that of a standard size work piece for the gage, said centers being spaced apart in the direction of relative motion of said anvils.

2. A pair of cooperating external thread gaging anvils relatively movable toward each other to'thread-gaging relation and from each other to open to receive or release a work piece therebetween, said anvils having adjacent faces substantially perpendicular to the line ofsuch relative motion and oppositely recessed to receive a work piece therebetween, the recessed face of one of said anvils having thread gaging ridges thereon through an arc of less than the recessed face in the other of said anvils adjacent to said perpendicular face having its marginal portions of cylindrical contour with a common center and of a diameter slightly larger than the major diameter of a standard work piece for said anvils, said recessed face of said other anvil at its said perpendicular face being of a width less than said major diameter, the intermediate portion of said recessed face of said other anvil having thread gaging ridges of a radius equal to that of said one anvil and described about a common center therewith and in the same helix when said anvils are closed together in standard thread size relation. 7

3. A pair of cooperating external thread gaging anvils relatively movable toward each other to thread gaging relation and away from each other to open to receive or release a threaded Work piece, one of said anvils having a recessed side face having thread gaging ridges in an arc of less than a semicircumference, the other of said anvils having a recessed face opposed to the recessed face of said one anvil, the outer portion of said other anvil recessed face comprising a pair of cylindrical arcs each of a diameter slightly larger than the diameter of the largest work piece to be tested by said gage and having a common center, the remainder of said recessed face of said other anvil between said cylindrical arcs having thread gaging ridges described about a center common to the thread gaging ridges of said one anvil when said anvils are in normal closed thread gaging relation and of a radius equal to that of a standard sized work piece for the gage, said centers being spaced apart in the direction of relative motion of said anvils.

References Cited in the file of this patent UNITED STATES PATENTS Gates et a1 Mar. 11, 1952 

